1. Field of the Invention
The present invention relates to a liquid crystal display and a method for manufacturing the same, and more particularly, to a liquid crystal display and a method for manufacturing the same that reduces the use of photolithography processes.
2. Discussion of the Related Art
In general, a liquid crystal display refers to a display device in which liquid crystal material with an anisotropic dielectric constant is injected between an upper transparent insulating substrate, typically used as a color filter substrate, and a lower transparent insulating substrate, typically used as an array substrate. An electric field applied to the liquid crystal material is adjusted in intensity such that the molecular arrangement of the liquid crystal material changes accordingly. Thus, the amount of light transmitted to the transparent insulating substrate through the liquid crystal material is controlled and a desired image is displayed. A common type of a liquid crystal display is a thin film transistor liquid crystal display (TFT LCD) using a TFT as a switching device.
In such a liquid crystal display, a mask process is commonly used to manufacture the print pattern of a thin film transistor, a color filter, and a black matrix. The mask process is accompanied by other processes such as rinsing, deposition, baking, irradiating, developing, etching, and peeling-off procedures. In the mask process, a large number of photoresists are required. Thus, manufacturing cost and process time are increased.
FIG. 1 illustrates a resist printing method according to the related art. As shown in FIG. 1, a template 11 with a transfer pattern (P1) first causes a pattern to be formed on print roll 10. Print roll 10 may have a silicon rubber surface. The print pattern (P2) is then transferred to the transparent insulating substrate 100. Thus, the print pattern (P2) is not directly transferred from the template 11 to the transparent insulating substrate 100 in the resist printing method.
FIG. 2 and FIG. 3 illustrate part of the print pattern of a related art liquid crystal display. FIG. 2 illustrates a gate line 110, a gate electrode 111, and an outer common line 120. The gate electrode 111 is connected to the gate line 110. The outer common line 120 is disposed along a region having an individual pixel formed therein. FIG. 3 illustrates a shape of a data line 130.
As shown in FIG. 2 and FIG. 3, the print pattern of the related art liquid crystal display is generally constructed to have a complex shape. Typically, the shape is angular rather than a simple straight-line shape. As a result, the print pattern of the related art liquid crystal display cannot be formed using a resist printing process. Rather, the patterns must be formed using a photolithography process, which increases the manufacturing cost and process time as a large number of photoresist steps are required.
To overcome drawbacks posed by the complex shape of the print pattern of the related art liquid crystal display, a straight-line shaped print pattern has been introduced to simplify the photolithography process. To the extent possible, the photolithography process is replaced by a resist printing process. In this approach, however, part of the print pattern is shifted when the straight-line shaped print pattern is formed using resist printing.
FIG. 4 illustrates a drawback of resist printing by comparing a pattern created by a mask pattern (P3) and a pattern created by resist printing, i.e., print pattern (P2). In general, a main drawback of resist printing is a stretched pattern resulting from a pushing motion of the print roll 10 as it moves across the substrate 100 to transfer the print pattern (P2). As shown in FIG. 4, horizontal shapes formed by the resist printing process, i.e., horizontal print patterns (P2), are stretched compared to horizontal shapes formed by a mask, i.e., horizontal mask patterns (P3). Further, positions of the vertical shapes formed by the resist printing process, i.e., vertical print patterns (P2), are shifted in the printing direction compared to the position of the vertical shapes formed by the mask, i.e., vertical mask patterns (P3). Accordingly, compared to the mask patterns (P3) formed by a mask process, the print patterns (P2) formed by the resist printing process are elongated and shifted from the desired position of the patterns.
The shifted and stretched portions of print pattern (P2) affect the performance of the liquid crystal display. For example, the shifted portions of print pattern (P2) cause a reduction in the aperture ratio and inaccurate alignment that results in light leakage.